


Skeletal Roommate

by Nashina



Category: Undertale (Video Game)
Genre: Accidental Voyeurism, Bara Sans, Bara!Sans, Big Sans, Big!Sans, Biting, Blowjobs, Choking, Crying, Cunnilingus, Dirty Talk, F/M, Face-Riding, Face-Sitting, Fluff, Ghost Penis, Kissing, Muah, PWP, Plot What Plot/Porn Without Plot, SO MUCH FLUFF, Tooth-Rotting Fluff, Voyeurism, blue ghost penis, i just love sans, idefk, possesive!sans, this is all over the place, you cry easily
Language: English
Status: Completed
Published: 2016-08-04
Updated: 2016-08-04
Packaged: 2018-07-29 05:48:48
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 3,698
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7672492
Author URL: https://archiveofourown.org/users/Nashina/pseuds/Nashina
Summary: <blockquote class="userstuff">
              <p>It was your first free afternoon in forever and you just wanted to masturbate in peace. However Sans comes home sooner than you thought. What happens when he sees you touching yourself in his bed AND his jacket?</p>
            </blockquote>





	Skeletal Roommate

**Author's Note:**

> This is ALL over the place man. I had a plot at the beginning, but fuck it. I like it so suck it.

His eyes slowly slid down your quivering body, halting at your breasts. He watched them heave with every ragged breath you took, before his eyes moved lower. He took in your tummy, your shaking legs until he finally looked at your core. His breath hitched as he watched your fingers plunge in and out of you, your other hand playing with your clit. It was extremely hard for him (no pun intended) not to go over there and touch you. But he couldn’t. After all you didn’t even now he was here.

He was coming home early from work. It was raining cats and dogs outside and no one would stop in the middle of the street to buy a hot dog so he figured why not get home sooner and spend some more time with his favourite human? When he opened the door he shouted his usual:” i’m home!” When he didn’t get an answer he wasn’t too worried. He knew that you usually sat in front of your computer and listened to music while writing. But when he couldn’t find you in your room nor the kitchen, he got worried. He went back to the entrance to see if your keys were gone. They were still here. So where were you?

As he wondered where he could look next he heard something. He couldn’t really tell what it was, but he knew it came from upstairs. So he ascended the stairs and waited for the noise again. It sounded like a..moan? And it was coming from his room! He saw that his door was slightly ajar. He never told you that you couldn’t go into his room, but you knew he was very peculiar about it. And you usually always asked! He turned off all the lights and opened the door further. Why he turned off the lights he didn’t know. It was just a…hunch.

When he opened the door further he saw that his bedside lamp was on and you were laying on his bed. Naked. Except for his favourite jacket. Seeing you in his clothes turned him on immensely. And seeing you masturbate in his own bed even more. Your eyes were closed so you didn’t notice he was standing right in the doorway, watching you.  
You rarely had an afternoon for yourself. Either Papyrus or Sans were home, or you had something to do. Job, laundry, cleaning. Of course you had your privacy in your room, but the walls were thin. Masturbating had to be stealthy. And you liked to be loud.

And the worst part? You had the biggest crush on your skeletal roommate. He may be the smaller one of the brothers but he still towered over you. Being a small human that was rather easy but still! When you came into his room you felt ashamed. You wanted to turn around and leave and never think about doing this again. But then you saw his jacket hanging on the back of his chair. You just couldn’t resist. Stripping off all your clothes you put on his jacket and fell face first on his bed. Since you helped him clean and he actually started doing his laundry, his room didn’t stink. It was messy, yeah, but didn’t stink. It smelled like ketchup, books and spaghetti. It smelled like home.

You turned around on your back and closed your eyes. Imagining him being here with you. You let your hands wander down from your neck to collarbones to your breasts. You squeezed and massaged them until your nipples got hard. Pinching and tweaking them you mewled and let one hand wander down lower. Softly scratching over your tummy down to your thighs you started to wiggle. Why were you teasing yourself? Before you could answer that question you put your hand down to your sex and slowly, just slightly, played with your clit. You thrust your hips up, needing more. Your mewls turned into whimpers. Slowly you let your hand go lower to your opening. You just circled it until you inserted one finger. You moaned while thrusting your finger in and out. Soon, another finger followed and your other hand started playing with your nub. Your fingers started moving faster and faster and soon you couldn’t contain your moans anymore.

“Ah~”

You turned around on your stomach, raising your ass up in the air. You could’ve sworn you heard something behind you, but you were in too deep to give a shit. You were so close. Speeding up as fast as you could you fucked yourself like never before.

“Ah! Oh my god I’m gonna come! Sans! _Sans_!”

You couldn’t enjoy your (amazing) orgasm because you **definitely** heard something. Slowly turning around, you saw Sans standing in the doorway, a blue dick wrapped in his phalanges and his hand and the floor in front of him covered in blue come.

“Oh-oh my god I’m so sorry!”, you squealed, jumping of his bed and running past him to the bathroom. What the hell did you do?? He’s going to hate you forever! You slowly slid down the door and sat on the floor. That’s when you noticed that you were still wearing his jacket. You felt how your juices slowly dripped onto it. Great, you thought. Now you had to wash it. Tears were forming in your eyes. He’s going to hate you. He’ll throw you out. He’ll never want to see you again. He’s going to tell Papyrus and Undyne and Alphys and everyone! You’re going to lose all your friends! But most importantly, you’re going to lose _him_.

You didn’t even notice you were full on crying when you heard a gentle knock on the door. “___? are you okay? please stop crying.” His gentle, deep voice only made you cry harder. “sweetheart please.” He tried to open the door. “baby, please unlock the door.” You sniffed and wiped away your tears. There were new ones coming immediately but it was worth a try. Slowly you stood up and zipped up the jacket. Thankfully it reached all the way to your thighs. You unlocked the door and stepped back.

“___?” The door carefully opened and Sans came in. His eyebrows were scrunched and his grin was upside down. The lights in his eyes were dimmer than usual but he still looked beautiful. Even know, disappointed as he must be, he still looked amazing. You didn’t know your crying got worse again until he was right in front of you. “babe. honey. darling. please stop crying.”, he begged and pulled you in a hug. “I’m so sorry. I’m so..so sorry. Please don’t..please don’t hate me. I’m sorry I’m sorry I’m sorry…” You were a mumbling whimpering mess. Sans pulled both of you down on the floor until he was leaning against a wall and you were sitting on his lap.

“sshh. it’s fine babygirl. i’m not mad. i promise. everything’s fine.” He whispered sweet nothings in your ear and rubbed soothing circles on your back.

After what felt like forever you finally calmed down. His hoodie now covered in your tears and snot. Sexy. “I’m sorry.”, you whispered. He gently pushed you away to look into your eyes. “how often do i have to say this. it’s fine. you’re fine. everything’s fine.” He held your face in his hands, your foreheads touching. “But how can you not be mad? I went into your room without asking, I stole your jacket, I masturbated in your bed!” A rich laugh filled the bathroom. “that’s supposed to make me mad? sweetie, it turned me on. it aroused me. you know how bad I wanted to get over there and fuck you into my mattress?”, he growled. Not even ten minutes earlier you were crying your heart out and now you were getting wet again. Suddenly you realized in what close proximity you both were and started breathing hard.

“S-Sans..” He just grinned at you, carefully wiping away your tears. “i really like you.”, he whispered. You smiled. “I really like you too.”

After setting you down on the toilet and getting a wet washcloth, Sans carefully cleaned your face and brought you some tissues. When you were presentable again he picked you up bridal style and carried you in his room. He laid you down on the bed, but before he could move away you held him back by his sleeve. “Don’t..go.”, you whispered. He just chuckled and unwrapped your fingers gently. “i was going to lie down next to you. don’t worry.” You just blushed and waited for him to lie down. When he did, you immediately curled into his side and pressed yourself against him. He just chuckled again and pulled you even closer. “…Are you sure you’re not mad anymore?” After kissing your head, he gently took your chin and made you look up at him. “i am flattered, but not mad.”,he smiled. And it seemed genuine. Your doubts grew smaller and smaller until they were non-existent. You didn’t fuck up. He’s not going to leave you. You’re neither going to lose your friends nor him. You might even be able to become more than friends.

His hand rubbed soothingly up and down your arm, while he covered your face in kisses. You started giggling and punched him slightly in the chest. He started laughing too and pulled you until you fully lay on top of him. You just stared at each other with his hands on your waist and yours holding his face gingerly. Gently smiling you lowered your face and kissed him. It was a sweet, short, soft kiss that neither of you will ever forget. His hands ran up and down your back, kissing you again and again. The kisses were sweet at first, loving. But they grew hotter and more passionate. Until suddenly, you gasped. “You have a tongue!?” He laughed, the sound making you feel all fuzzy inside. “yup. and that’s not the only thing i have.” Before you had the chance to question him, you felt a bulge press against your bottom. For the probably hundredths time today you blushed and buried your face in his neck. His hands went back to their original position on your waist.

“is it too much? i can stop if you want.” You quickly shook your head. He was so gentle and nice. You trusted him. He always cared for, looked out for you, made you laugh. You would trust him with your life in his hands. “It’s never too much, when I’m with you.” As to further conduct your point, you ground your hips. That earned you the most delicious groan yet.

 

“babygirl, you probably shouldn’t have said that.”, he growled while his hands gripped your ass, hard. You moaned out and bit down on his vertebrae. He growled again and swiftly flipped you over so now he was on top. The only way to describe his facial expression was animalistic. His grin seemed feral, his tongue hanging out and you could clearly see his sharp canines. His left eye was set ablaze by an ever changing blue and yellow fire. The only thing you could do was stare, but thankfully, you didn’t have to do anything else. He bent down and hungrily kissed you while opening your (his) jacket. You squeaked and tried to cover yourself. “baby, i’ve already seen you like an hour ago.” You just pouted and let him take your hands off gently. Then he just looked at you. Without doing anything. Just looked. You were getting uncomfortable and started squirming around. He took your wrists and held them above your head before dipping down and nibbling on your neck. “you.” He kissed down to your collarbone. “are.” He kissed down the valley between your breasts. “so.” He kissed your stomach and dipped in your navel with his tongue. “beautiful.” He got back up and looked you in the eyes. You could see a little heart where his pupil was supposed to be. You smiled and pulled him down for a kiss.

This was the most passionate kiss of them all. You carefully moved your lips against his teeth, when his tongue asked for entrance. Of course you immediately opened your mouth for him and his tongue intruded. It explored every nook and cranny. After licking over all your teeth and deep inside your mouth (you almost gagged) his tongue wrestled with yours and you thought for dominance. He won but let you come up for fresh air. While you tried to catch your breath, Sans kissed down your neck to your boobs. He massaged one with his hand, while licking all around the other. You moaned into your fist when he gently bit your nipple. “S-Sans~” He immediately stopped. “did that hurt? did I hurt you?”, he asked concerned. You looked at him surprised before smiling. “No.. That was a good sound.” A blue blush started spreading over his cheekbones. “okay.”

Before he could continue his ministrations you were able to flip the both of you again. “My turn.”, you grinned and helped him take off his hoodie. Now it was all turned around. He was shirtless and you were staring. His blush darkened and he looked everywhere but you. You giggled and kissed him softly. “You’re also very beautiful.”, you smiled. He just stuck his tongue out at you which you quickly licked. While he was too busy being flustered, you kissed his neck vertebrae, his clavicle down to his ribs. First you just gently kissed them and ran your nails over them. When you reached the bottom, you licked your way back up. His groans, moans and growls were music in your ears. You wanted to hear more, to make him louder. You kissed, licked and nibbled on his lowest rib and at the same time you let your nails scratch them on the inside. Then you had an idea. While still biting and licking his clavicle, you gripped his spine. “ _sh-shit_.”, he moaned and you grinned. Your hand stayed on his spine, moving like it would on his cock. You kissed your way down again until you reached his pelvic bone. Licking and biting it you realized, there’s a bulge that shouldn’t be there. Carefully removing Sans’ shorts you saw the blue ghost dick from earlier. You stared in awe, wondering how it worked. But you decided to ask another time. One hand still working on his spine, your other hand gripped the base of his shaft.

“shit kid.. you really know what you’re doing, huh?” You actually had no idea but didn’t say anything. You kissed the tip of his cock while your other hand slowly moved from his spine to his shaft. Licking it up and down you made it slick with your spit. His moans and groans grew louder with every minute. You loved it. You took the tip in your mouth and moved your hands up and down. You needed both of your hands because his cock had an abnormal width. You had no idea how that was going to fit inside you, but you had hope. Moving you’re head slowly, he gripped your hair.

“fucking shit, princess. who..who taught you that?” He didn’t seem to want an answer, because he gently moved your head. When his grip got harder you moaned. “oh god do that again!” So you kept moaning, moving your head and hands until- “okay. no. no no no you need to stop. i don’t want to come yet.”, he quickly said and pulled you off his cock. There was a long thread of your saliva connecting you until Sans pulled you up again. “i wanna try something.”, he said and laid down on his back. “sit on my face.” What. “What!?” He laughed and looked up at you, gripping your thighs. “sit on my face, facing me.” With the darkest blush you’ve ever had, you did what you were told and sat down.

“good girl.”, he said before gripping your ass cheeks and spreading them. You felt his tongue lick up your slit and wiggle shortly at your nub. You moaned, wriggling your hips. “stay still, baby. works better that way.” After saying that, his tongue gently prodded at your entrance and entered. Being made of magic, he could make his tongue as long and as thick as he wanted. He reached every sweet spot inside you, and found new ones. Your hands gripped his ribs and you started riding his face. His grip on your ass got harder. He knew you were close.

“S-Sans! I’m…I’m going to-!” A hard, boney slap on your ass interrupted you. “not yet.”, he growled but kept fucking you with his tongue. It was so hard not to come. Too hard.

“Sans! Sans stop or I’m going to..! I’m..! I’m sorry!” You came as hard as you never came before. But for the second time this day, you couldn’t enjoy it. Because you were thrown of your skeletal roommate. “Sans!”, you squeaked, now laying on the edge of the bed on your back.

When you looked at him, you were scared. His fangs seemed to have grown and his eyes were pupil-less. Not even the blue fire was there. “Sans I’m-!” “i told you not to come.”, he growled. You started shaking. As afraid as you were, you were at least twice as much turned on.

“Sans I…” Suddenly he was on top of you, his face only inches away from yours. “ssh. you know, i’m kind-hearted. i won’t punish you. however, i _will_ fuck you. and if you make any noise before i allow you to, _y o u ‘ r e g o n n a h a v e a b a d t i m e_.” A shiver ran down your spin and you swiftly pulled him down and kissed him, hard. He growled into your mouth when you pulled him closer by is spine and hooked your legs around him.

He positioned himself in front of your entrance, covering himself in your juices. “you ready?” You wanted to say yes, but then you remembered his promise. You nodded. He grinned and slowly pushed the tip in. It was as big and as painful as you imagined. He’s a gigantic monster, of course his dick is going to be bigger than any humans. You bit your lower lip as to not make too many sounds and grabbed at his skull.

Slowly, he inched inside you. He payed a lot of attention to your facial expressions and always stopped when you seemed to be in pain. When he finally halted you thought you were going to break. “you’re so..fucking..tight..”, he groaned into your neck. Tears were rolling down your cheeks and your lip had started to bleed. When he looked at your face, a look of arousal and love washed over it. He licked away your tears and softly kissed you. “i’m here baby. don’t worry. everything’s going to be fine.” You smiled and kissed his cheekbone.

You two stayed there for a while. Kissing, touching, licking. Until you finally adjusted and wiggled a little. “can i move?”, he asked gently. You nodded again and he started to pull out. Only a little. When he pushed in again you wanted to scream. It still hurt, a lot. But you were determined to get through. You just kept telling yourself it was going to feel amazing soon.

“i’m sorry, baby. if it’s too much you can tell me.”, he said worriedly. Then he grinned. “but only if it’s too much.” Before you could react in any way, he pulled out and when he pushed in again, he found the spot. “Sa-mmmmmh!!” You pressed your hands over your mouth. “oh? have i told you to speak yet, kitten?”, he asked and slammed back against the spot. You bit into your hand but it was not enough. You grabbed his clavicles. “Sans please fuck me! Fuck me harder!” His grin turned ferocious and his thrusts unforgiving. “i. haven’t. told. you. to. speak.” With every word he thrusted deep and hard inside you. “I’m sorry I’m sorry just please Sa-!” Suddenly there was a hand wrapped around your throat. You tried to speak but he cut off all your air. “i told you i’d punish you.”, he growled. For a second you could breathe, because he turned you around. But then he pulled you up by your throat and pushed back into you. “you like that? you like getting fucked from behind while you can’t breathe? you know what would make it even better?” You quickly shook your head. And then you felt his teeth sink into your neck. You automatically wanted to gasp and thankfully, Sans let you. “oh _fuck_ you taste good.”, he moaned as he lapped up your blood. “i want to mark you all over. i want to cover you in bruises and bitemarks. i want everyone to know you’re mine and mine only.” His possessive growl almost sent you over the edge but you held back.

His pounds became animalistic and sloppy. “baby, are you close? i want you to scream my name when you come. you hear me? _scream my name_!” It only took you a few more thrust before you came screaming his name. Not even three thrusts later, he came deep inside you with a deep growl of your name.

You fell face first on the bed and Sans right beside you. Breathing heavily, you rolled onto him. “hi there.”, he grinned. “Hiya!”, you answered, giggling. “you feeling okay? was i too rough? should we disinfect the bite? oh my god i didn’t think this through.” The worried expression on his face and the returning sweat-drops on his skull were hilarious to you. “Sansy I’m fine! It probably needs to be disinfected but that can wait.”, you laughed. “nope.” He stood and picked you up carrying you to the bathroom. “big sansy wants you to be perfectly healthy.”, he winked at you. You giggled and kissed his cheek. “Thank you.”

**Author's Note:**

> Enjoyed? Check out my other Fanfics and sin with me on tumblr! @Nashina


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